Refuse burning furnace



Nov.- 16, 1937. M A, HOFFT l 2,099,522

REFUSE BURNING FURNACE Filed Feb, 8, 1936 2 sheets-sheet 1 INVENTOR.

.yrce A. Hoffi'.

wave( NOV. 16, 1937. M A HOFFT I 2,099,522

REFUSE BURNING FURNACE Filed Feb. 8, 1936 2 Sheets-Sheet 2.

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ATTORNEYS'.

. l I INVENTOR'. l Mawr/)ce .14.Hof/` Patented Nov. 16, 1937 UNITEDSTATES PATENT OFFICE REFUSE BURNING FURNACE Maurice A. Hoift,Indianapolis, Ind.

Application February 8, 1936, Serial No. 62,887

3 Claims.

My invention relates to improvements in furnace grates and particularlyto furnace grates of the pusher type, adapted primarily for burning suchfuels as refuse, waste, rubbish, garbage,

and other like material. More specifically my vention relates to meansfor water cooling furnace grates of the pusher type. character thegrates become extremely hot and a result of the intense heat and the heIn grates of this there are certain occasions where as ating 'of thegrates to a high temperature, certain objections arise.

For instance, the grates may become warped under the intense heat, thegrates may be caused to swell under the intense h eat until theassociated parts become stuck together,

preventing theoperation to a certain extent the pushers.

Furthermore, under this intense heat certain types of refuse tend toform intoy a hard slag almost like glass, which is extremely dilcult toremove from the grates and which materially affects the operation of thegrates.

By'providing means for cooling these grates of the pusher type, I amenabled to reduce the temperature of the grates and grate bars to suchan extent that the above diflculties are overcome.

For the purpose of disclosing my invention, I

have disclosed certain embodiments thereof the accompanying drawings inwhich:

Fig. 1 is a. longitudinal sectional View of a boiler embodying myinvention;

Fig. 2 is a detail plan view of a portion of the grate structure;

Fig. 3 is a detail side elevation of a portion of the grate structure;

Fig. 4 is a detail section on the line 4-4 Fig. 2;

Fig. 5 is a longitudinal sectional view of a modification of myinvention; and

Fig. 6 is a detail section on the line 6-6 Fig. 5.

In the structure illustrated in Figs. 1 to 4 clusive, the boiler I isprovided with a plurality of. water-cooled tubes 2 arranged side by sideand extending from the front to the back of the furnace, the grate beinginclined downwardly ward the rear of the furnace, as shown.v These tubesare connected in a water circulating s which the air may be admitted tothe fuel.

OIl

each side of the pusher bars at their fore ends, I provide a trunnion 6by which the pusher may be supported in position. The hollow pushers, ineffect, have spaced apart side plates 1 through which the openings 4 areadapted to be formed and these side plates are substantially triangularin elevation, having forwardly extending lower ends 8. The pushers aresupported in grate bar members 9 which are provided with side webs I0extending a considerable distance downward and having trunnion receivingslots II formed in the upper face thereof. Transversely extendinglingers I2 are formed on the inner faces of the side bars III adjacentthe pushers and the trunnion receiving slots are sufciently spaced apartto provide a certain spacing from front to back of the pushers. Thisspacing is provided with transversely extending webs I3 extendingbetween the side webs I0. The structure thus described constitutes ineffect a grate bar provided with means for supporting therein aplurality 'of pushers, one disposed behind the other fromfront to backof the furnace. These grate bars are supported upon and at leastpartially cover the tubes 2 and to this end, each of the grate bars onits sides is provided with a laterally extending flange I4 having formedon its under face an arcuate surface I5 which fits over and receives atube 2. This flange I4 may, if desired, be extended a sufiicientdistance to cover the tube to the center thereof so that when all of thegrate bars are in position, the entire surface of the tubes will becovered, or it may be short, as is illustrated, to leave a certainportion of the top of each tube exposed. The lower end of each of thepushers which, while having been described as having been substantiallytriangular, is as a matter of fact somewhat arcuate Vin shape, and isconnected to an operating rod I6 extending out through the furnace wallin order that the pushers may be manipulated from the exterior of thefurnace. There are a series of these grate bars with their pushersarranged between each pair of longitudinally extending tubes and thepushers are preferably arranged so that transversely of the furnace,parallel rows of pushers are provided. By this arrangement, the lowerends of each of the transversely extending rows of pushers may beconnected to a single operating rod, in turn connected to the operatingbar I6 so that each of the series of. pushers may be operatedsimultaneously although from front to back of the furnace, the series ofpushers may be operated independently and as a matter of fact, areoperated progressively.

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In the structure illustrated in Figs. 5 and 6, I have shown a modifiedform of furnace. In this structure, the initial portion of the grate ispreiferably formed of. tile as at 2| and this portion of the grate hasan angle of inclination of about fifty degrees. The next portion of thegrate preferably consists of longitudinally extending tubes 22,preferably connected respectively at one end with a header 23 and at theother end with a header 24. That portion of the tubes next adjacent tothe hearth portion 2| of the grate is preferably given an inclination ofabout fortyve degrees. These tubes 22 are bent at their lower ends sothat the lower end of the grate will have an angle of inclination ofabout thirty degrees. The tubes may be bent at the point 25 to give thischange in angle of inclination or, if desired, a header may be insertedat this point. Supported on the tubes are the pushers and grate bars ofthe construction heretofore described and above this portion, Ipreferably mount stationary grate bars 26 which, as will be seen incross section, are provided with webs embracing the sides of the tubes.

In this arrangement, the material is rs't dumped upon the hearth section2| and because of its wetness and therefore being slow to move, theinclination of the hearth section advances the material. As it gets downto the next section which has a less inclination it has become somewhatdried and, therefore, will have a tendency to move more rapidly. Due tothe difference in the angle of inclination, however, the moven ment ismaintained at about the same speed. As it finally reaches the lowermostsection of the grate, it will have become more or less coked andcomparatively dry so that on this section the inclination is less thanthe other two sections, and this section is provided with pushers notonly for the purpose of breaking up the coked material but also fo-r thepurpose of moving it on down to the delivery end of the grate.

It is quite obvious that while I have shown round tubes, tubes havingother cross sectional configuration may be used, such, for instance, asrectangular tubular constructions or the like.

It is also obvious that the headers for the ends of the tubes may be ofany suitable construction, either rectangular or round or of any otherdesired configuration.

I claim as my invention:

1. In a furnace, in combination, a plurality of Water tubes extendinglongitudinally of the furnace from front to back, a plurality of gratebars, each having comparatively deep vertical side walls having notchesin their upper edges to receive pusher finger trunnions and connected ontheir top faces by a series of cross bars and having on their innerwalls transversely extending ngers, said grate bars occupying the spacebetween said tubes and pusher fingers mounted in the spaces between saidinwardly projecting ngers and having trunnions pivotally supported inthe trunnion notches in the grate bars.

2. In a furnace, in combination, a plurality of water tubes extendinglongitudinally of the furnace from front to back and spaced apart, aplurality of grate bars occupying the space between and supported uponsaid water tubes and cach comprising a pair of vertical side wallscomparatively deep, having recesses extending longitudinally thereof toreceive said water tubes, the

.top surface of said side walls being connected the side walls beingprovided on their uppery faces with trunnion notches, and pusher fingersfitting between the side walls and having laterally extending trunnionspivotally engaging in said trunnion notches, l

MAURICE A. HOFFT.

